After graduation Dr Chang followed his passion on the pursuit of academic research and teaching. He has now accumulated over 25 years of teaching and research experience. His university teaching covers mainly Internet protocols, data structures and algorithms, and programming. In 2001 he was awarded the First Runner-Up in the Faculty of Engineering's Best Teacher Award, in 2009 and 2012 the Faculty's Industrial and Engineering Services Grant Achievement Award, and in 2014 the Most Active New Consultant Merit Award. He is a member of IEEE and ACM.

Dr Chang's research interests include network measurement, and network operations and management problems. The Group has published their findings in top conferences, such as CoNEXT, USENIX Annual Tech Conf, IMC, INFOCOM, DSN, and NOMS. His recent research activities are generously supported by the Innovation Technology Fund, The Joint Universities Computer Centre, Areas of Excellence Scheme in Information Technology, the Research Grant Council of Hong Kong, Cisco Inc., and The Hong Kong Polytechnic University.

Dr Chang was the warden of the LiZhi Hall during 2008-2013 and had been responsible for the department's placement and WIE programs for a long time. He is currently the chairman of the Departmental Undergraduate Program Committee and in charge of the academic adivising. He is also organizing CSI! Inception and Hackathon to promote creativity and dare-to-think spirit among Freshmen and Sophomore.